Saw IV (2007)
During John Kramer's autopsy, a wax-coated microcassette is found in his stomach. Detective Mark Hoffman is called in to hear the tape, which reveals that he will still be tested, and that the games will continue. The scene cuts to a mausoleum, where Art andTrevor awaken chained at the neck to a winch. Trevor's eyes and Art's mouth are sewn shut, making communication impossible. In a blind panic, Trevor activates the winch and attacks Art, who kills him during the struggle, and takes a key from Trevor's collar to free himself. Four days after her death, Allison Kerry's body is found by a SWAT team. After cautioning Lieutenant Daniel Rigg for breaking through an unsecured door to reach her, Hoffman sends him home. He is then met by FBI Agents Peter Strahm and Lindsey Perez, who were contacted by Kerry before her death. They believe that an unknown accomplice set up Kerry's trap, as John and Amanda Young were physically incapable of putting Kerry in the harness. Strahm soon becomes suspicious of Rigg, who has developed an obsession with saving everyone and is convinced that Detective Eric Matthews, who vanished without a trace six months earlier, is still alive. Rigg returns home just as his wife is leaving to be with her mother, and declines her plea for him to accompany her. That night, Rigg and Hoffman are attacked by pig-masked figures. Rigg awakens in his bathroom and learns that Matthews is alive and has ninety minutes to save himself, with Hoffman's life at stake as well. In the meantime, Rigg must undergo his own tests in order to face his obsession and "truly learn how to save a life". His first test is in his living room, where Brenda, a pimp, is bound to a chair and wearing a pig mask. Rigg is implored to walk away, but he accidentally activates the trap by removing her mask, which slowly tears her scalp. He succeeds in freeing her, only to kill her in self-defense when she attacks him with a knife: she had previously been told by tape that Rigg would arrest her, and killing him was the only way to stop him. While the agents investigate the scene, Strahm finds a clue that points to Jill Tuck, John's ex-wife, and she is brought to the station for questioning. A man arrives at the room where Matthews and Hoffman are being held, to oversee their game. Matthews stands atop an ice block with a chain-noose around his neck on one end of a large see-saw, and Hoffman is strapped to a chair with electrodes at his feet on the other end. If too much ice melts or Matthews jumps, he will be hanged and Hoffman will be electrocuted, killing them both. For his second test, Rigg is led to a motel and is instructed to abduct the owner, Ivan Landsness, and place him in a prearranged trap in one of the rooms. After finding photo and video evidence that Ivan is a serial rapist, an enraged Rigg forces Ivan into the trap and leaves after handing him two controllers. Ivan's test requires that he blind both eyes with blades, but he only succeeds in blinding one eye before the timer expires and the trap dismembers him. Meanwhile, the agents alternate between investigating the scenes of Rigg's test and questioning Jill, who reveals John's backstory. He was a civil engineer involved with property development, while she ran a clinic to help drug addicts. She was pregnant with their baby, to be named Gideon after John's first building project with Art Blank, and Jigsaw's puppet was designed as a toy for him. Seven months into her pregnancy, her clinic was robbed by an addict named Cecil Adams, and she miscarried when Cecil slammed a door into her stomach while fleeing. The agents are called to the motel, where they learn that they are now targets and that the room was rented out to Art Blank, who vanished two weeks prior. The man overseeing the current game is revealed to be Art when he prevents Matthews from jumping and hands him a gun. In his third test, Rigg enters an elementary school and finds Morgan and Rex, a woman and her abusive husband, impaled together by rods in a harness. The rods pass through vital circulatory points in Rex's body, but non-vital points of Morgan's. By the time Rigg arrives, Morgan has removed all but one rod and passed out from shock, her husband long since dead. She wakes up and Rigg pulls the last rod from her body and gives her the key to her harness, telling her she has to save herself. He then finds the location of his final test and leaves, pulling the fire alarm on his way out. The agents learn at the scene that all three dead victims were represented in court by Art, who was also Jill's lawyer. They find Jigsaw's puppet in another room, where a cryptic message is played for Perez before the puppet's face explodes, sending shrapnel into her face and neck. After she is hospitalized, Strahm furiously interrogates Jill, now convinced Art is the accomplice. She reveals that John's depression following the miscarriage ended their marriage as well as his partnership with Art, and that after surviving his suicide attempt he began his work testing others. His first victim, Cecil, was to push his face through several knives to release his razor blade arm and leg restraints. The trap collapsed, but Cecil died anyway when he lunged at John and fell into a tangle of razor-wire. Strahm connects her story and a prior clue to the Gideon Meatpacking Plant, the location of Rigg's final test. He arrives shortly after Rigg but ends up trailing Jeff Denlon, arriving in front of the door to the sickroom just as it seals itself. He unlocks it using Kerry's key and finds Jeff, only to shoot him dead in self-defense when Jeff points a gun at him, demanding to know where his daughter is. Meanwhile, Art pulls out a small device and explains to Matthews and Hoffman that he can use it to release all three of them when the timer expires. If he tries to do so before then, a pair of pincers will sever his spine. Unaware of this, Rigg arrives and breaks into the room with one second to spare, just as Matthews shoots him, releasing two overhead ice blocks that swing down and crush Matthews' head, killing him. A mortally wounded Rigg shoots and kills Art, believing him responsible for the game, and learns from Art's tape recorder that he failed by interfering: Matthews would have lived if Rigg had not gotten involved. Hoffman, the real accomplice, releases himself from the chair and leaves Rigg to die, before sealing Strahm in the sickroom and leaving the plant. The scene then cuts to John's autopsy, which took place ''after''the events of the film.